Quote:
Originally Posted by leviterande
What I am wondering is why is the metal detector only capable of detecting for a range of only a few feet? The metal detector is similar to any radio Tx/rx.
|
A metal detector coil is similar to a loosely coupled transformer, and a metal target that gets close to the coil will couple some of the TX energy into the RX coil. In effect, the metal target is acting like the core of the transformer. The main reason why a detector is restricted to a few feet in detection distance is because reactive effects cause the near field energy to fall off as a function of 1/d^3. Eddy currents generated in the target will then create their own magnetic field (Lenz's Law) and the return signal is subject to a 1/64 response.
If you haven't already read it, I would suggest you get a copy of "Inside the METAL DETECTOR" ->
http://www.geotech1.com/forums/conte...metal-detector
And ... I wouldn't waste any time with L-rods or MFDs.